1. Field of the Invention
The present invention is directed to wireless networking. Specifically, the invention pertains to a method of operating a wireless station using directional antennas.
2. Description of the Related Art
Wireless networks have enjoyed tremendous popularity in recent years. A consequence of increasing deployment of wireless networks, coupled with limited number of channels and unlicensed spectrum usage, is that the interference between transmissions is becoming a serious problem.
Using directional (or sectorized) antennas is a method to reduce the interference and to increase the range and the capacity for wireless networks. In general, network capacity is increased as a consequence of spatial spectrum reuse, and transmission range is extended due to the increased gain from directional transmission.
Directional antennas have also been proposed to improve the performance of 802.11 based wireless networks. However, the original 802.11 protocol was not designed for directional antennas. It assumes that all the frames (RTS/CTS/DATA/ACK frames) are transmitted as omnidirectional signals that are received by all nearby wireless stations. When directional antennas are used, new problems such as the enhanced hidden station problem and the deafness problem, arise. They increase the likelihood of collisions. A satisfying solution completely within the 802.11 framework has not yet been reported. What is needed is a new scheme for fully exploring the potential of directional antennas with the 802.11 protocol.